Extruded or Ball Power.

[tkcomer]

I'm loading for a 308 gun (DPMS LR-308B with a Krieger barrel) and I'm using Sierra match bullets. All I have right now is Tac powder. Is extruded powder that much better for precision rounds? I'm shooting about an inch and a half groups at 100 yards with 40.5grs of Tac. A lot of times, right at an inch. Any higher, I can get a little better, but the 10 round groups seem to open up. They're not as consistent as the 40.5grn load. Any help would be appreciated.

 

[helotaxi]

I've never had good accuracy results with TAC, others have. The particular powder/bullet/rifle combination has infinitely more to do with accuracy than whether the powder is ball or extruded.

The major differences between the two powder types revolve around convenience and stability, not accuracy. Extruded powders tend to be less temp sensitive but can be more difficult to measure and load into the case. Some of the newer extruded powders have very tiny kernels to minimize this inconvenience. Ball powders are very easy to measure and get into the case but are typically much more temp sensitive.

All that said, I've had excellent accuracy results with Varget and others have reported excellent results with IMR 8208XBR in the .308. You didn't mention what bullet weight you're using.

 

[tkcomer]

Oops, my bad. It's the 168 Match King. Experimenting with the 155grn match HPBT. Starting to see more consistent results with those, but I'm just starting. My gun has a 1X12 twist rate.

 

[Galil5.56]

I have definitely found when I switched from CCI 200 to CCI 250 primers (in .243) using ball propellants (H414/WW 760) groups shrunk by a lot, but even the std primers were very sub MOA, but fliers cropped up with my super heavy custom varmint rifle. All my rifles can all shoot very well with proper load development, be it using ball or extruded, and AA 2520 spherical is not dubbed "Camp Perry Powder" for nothing. I load AA2460 and H335 in .223 and .308, and although nothing I would consider "super precision", still delivers good performance for my needs.

Also, I find loading to a higher velocity and or load density with ball propellants is especially beneficial. Some may say temp variations cause huge swings in velocity (and pressures) with many ball propellants, but my chronograph measurements don't show me anything out of the ordinary, and accuracy remains great at any temps I have tried. Good luck!

 

[Jim Watson]

I never got the accuracy I wanted with AA2520 and changed to Varget. Reloder 15 is a good powder in that range, too.

On the other hand, a ten shot group is very demanding. NRA once computed that a ten shot group will average about 30% larger than a five shot group. That just on a statistical basis, even if you don't get tired and pull a shot while working at it twice as long.

 

[MEHavey]

Not a DPMS, but an M1A 1:11 twist w/ Nat'l Match rear sights/aperature.
At least half of that group is my aging eyesight:



And on the 8th day, God invented IMR4895.

 

[TonyT]

IMR-4895 has a smaller cut than most extruded powders and measures a bit more uniformly. When I loaded 308 Winchester and 30-06 match ammo I used either IMR-4895 or IMR-3031.

 

[Ky Larry]

I've read about universal loads and "ice cream" loads but have never seen it work. Every gun is a study in ballistics unto itself. I haven't found any rule that says use ball powder for X caliber and stick powder for Y caliber. I have very good .308 loads with IMR-4320 and AA-2450. The reason there are so many powder types listed for a particular bullet is that every rifle is different. In almost 40 years of reloading, I still haven't found a shortcut to load developement. The only way to find the best bullet-powder combo for your rifle is to load 'em and shoot 'em.

 

[Edarnold]

Ball powder vs. extruded

Some of the choices depend on how you plan on using the rifle. If it's for competition where you are firing 50+ rounds without cleaning, how much residue the powder builds up becomes a factor. Ball powders, to achieve desired burning rates, depend primarily on additives and coatings for progressive burning and flash suppression. By their nature, they contain more material that is not going to burn away completely. The classic example of this difference was the switch from extruded to ball powder in the ammunition for the M-16 during the Vietnam conflict, and the resulting furor over the malfunctions in a gun that had been faultless.

I agree with the suggestion of 4895 as a great powder in .308, also the VV powders N-140 and N-150, which are noted for being the cleanest burning propellents available.

 

[tkcomer]

I've always "heard" the comp shooters use extruded. I've "heard" the match powder for the military in 308 is RL-15. The gun didn't do that bad yesterday. Still a one and a half inch gun. I had the only 308. Still, the gang shot amazing groups with Win 748 in their 223 ARs. I may have access to some IMR 4895, but not enough for a full ladder test. And I try to buy in bulk. Which is why I have so much Tac laying around. But I'd still like to try and get this gun down to a consistent 10 round 1 inch group.

 

[Slamfire]

I prefer stick powders to the ball powder I have used. I bought kegs of AA2520 when it was cheap, it shoots well but it leaves lots of residue in the gas system and I have experienced "settling" at long range.

When I shot AA2520 out to 300 yards but used well characterized long range loads with stick powders, I got wild shots for the first two sighters and unpredictable shots for the next two to three rounds. It takes time for the point of impact to settle. This is not acceptable in a rifle match. I never had had this issue going from stick to stick.

In my opinion, IMR 4895 is the “standard” for the 308 in gas guns. You either go faster or a bit slower. I would stay within the same guidelines that are used in M1a’s, that is nothing faster than IMR 3031 and nothing slower than IMR 4064.

IMR 4895/AA2495/H4895 are close copies of each other, AA2495 gives the same pressure curve and is a copy of IMR 4895, but stupidly Accurate Arms gave it a different name and that confuses everyone. Buy by price.

I can recommend IMR 4064 but charges have to be weighed as it does not throw well. Varget is an outstanding powder, little slower than IMR 4895.

All things equal, faster powders are better than slower in gas guns.

A standard match load for decades was a 168 SMK 41.5 grains IMR 4895 LC cases , use CCI #34’s, OAL LT 2.800”

Since your barrel is a Kreiger barrel you must cut your loads as Kreiger barrels are tight. Try 40.5 grains IMR 4895/AA2495/H4895 and carefully work your way up.

 

[mnhntr]

Varget is your friend

 

[tkcomer]

40.5grs of IMR 4895 is a mid range load according to my ancient Sierra book. I'm using LC military surplus brass and I don't like to load in the upper ranges. I'll borrow some powder and give this load a try.